206 



Bursting of an open Boiler. 



sketch {Jig. 61.) of the apparatus which was used; the object 

 being to heat a small room. In the figure, a is an outer, 





h an inner, vessel, leaving a space (c) between them, to be 

 filled with water; d is the tube by which the water passes 

 from the boiler [e) into the space (c) ; and/" is the pipe by 

 which the water returns to the boiler. By this description, 

 and the course pointed out by the arrows, you will readily 

 perceive the manner of the circulation. The vessel a b was to 

 have a cover, as shown by the dotted lines ; but, as the cover 

 was not on at the time of the explosion, it may be put out of 

 view in respect to your object. The apparatus had been up 

 some days ; and I was standing alongside of it, watching the 

 circulation, when suddenly the water rose nearly to the top 

 of the vessel (« b), showing that the boiler must have been 

 emptied of all the water ; and suddenly a slight explosion 

 took place at the flanch at the top of the boiler, and a large 

 body of steam issued from the boiler for some time ; when. 



